It's hard to predict the future because we humans prefer to think in terms of familiar paradigms. Even the most brilliant of our species are subject to this flaw. Now, Microsoft faces its turn. The owner of the operating system that likely runs your personal computer, the company that achieved monopoly with Windows and ducked the Department of Justice's scythe to keep it, faces a midlife crisis as the world goes gaga over portable consumer devices. This is the story of what's happening to Microsoft in the handheld operating system markets -- and how it parallels the earlier, similar journeys of IBM Corporation and Digital Equipment Corporation. Can Microsoft achieve dominance on mobile devices?